The gerbil's whole nerve taste response to sucrose is specifically suppressed by methyl 4,6 dichloro 4,6-dideoxy alpha-D-galactopyranoside (MAD-diCl-Gal), p-nitrophenyl alpha-D-glucopyranoside (PNP-Glu) and chloramphenicol (CAP). To understand the nature of these antagonists, we will to conduct a number of experiments to determine whether the gerbil's behavior can be modified by adding these antagonists to taste solutions. In taste aversion studies, we found previously that the gerbil's avoidance of sucrose solution can be overcome by the addition of high concentrations of PNP-Glu. When mixtures of NaC1 and PNP-Glu were tested in gerbils trained to avoid sodium chloride there was no effect on their behavior. In the first part of proposed work we want to extend our findings to the other two antagonists, MAD-diCl-Gal and CAP. In the second part of proposed work, to fine tune our understanding of the sweet taste receptor, we will to test mixtures of the antagonists and sucrose on single neuron response. One potential use in humans of the sweet taste antagonists is the control of sugar intake. In the case of obese or diabetic individuals, it would seem desirable to diminish the hedonic properties of their foods which contain a lot of sugar.